1. Field of the Invention
This invention relates generally to manually manipulated tong wrenches used for making and breaking joints between adjacent threaded tubular members and more particularly to a hand manipulated tong wrench tool having adjustable, tactile indication of the torque force being applied to the tool.
2. General Background
In the Oil and Gas industry it is common practice to make up or couple threaded tubular members in order to provide extended strings of pipe, tubing, etc. The wrench or tool utilized to provide the torque necessary to assemble threaded tubular elements is known as a pipe tong. The tong is a specific type of wrench or tool that typically includes a set of articulated jaws containing dies for grippingly engaging the exterior diameter of one of the adjacent threaded tubular members. The other member is held stationary with respect to the first member and an actuating force is applied to a tong handle so that the necessary torque may be applied to the first member to make up or break out the threaded interconnection.
Manually operable tongs typically may contain two or more pivotally interconnected jaw members that may be closed into gripping engagement about a threaded member in anticipation of the application of a torque thereto. When the application of the force is completed, the jaws are opened so as to permit removal of the tongs from around the pipe joint. The handle is the moment arm through which the force to effect the make up or break out of the threaded joint between the members may be applied. Such manual tong tools may be relatively small for hand operation on small diameter threaded tubular members or relatively large for use in making up down hole, large diameter threaded tubular members. Examples of such hand tools are disclosed in U.S. Pat. Nos. 1,334,250, 2,093,788 and 4,289,021.
Alternatively, there are arrangements known in the art as power tongs whereby the jaws are disposed in a housing circumferentially encompassing the bore opening and through which protrude the threaded members. This tong""s arrangement is typically hydraulically operated and includes a tong lift arrangement whereby the tongs are raised and lowered to a predetermined operating position about a horizontal datum at which the joint to be made up or broken-out is located. One set of jaws, (the xe2x80x9cback-upxe2x80x9d jaws) is then moved radially inwardly into gripping engagement with one of the members while another set of jaws (the xe2x80x9cdrivenxe2x80x9d jaws) are moved into gripping engagement with the member which is to be rotated with respect ,to the first. A hydraulic tongs motor or the like applies the force, which is used to effect the make up or break out of the joint between the adjacent threaded members.
In the case of both the manual and the power driven tongs, it is advantageous to have some indication as to the magnitude of the torque applied to the threaded member. This indication has utility, for example, to prevent the application of excessive torque to the threaded member. Such torque sensing tools are disclosed in U.S. Pat. Nos. 4,137,758, 4,289,021, and 5,509,316
In the power tongs arrangement it is conventional to provide some feedback signal from the hydraulic tongs motor indicative of the amount of hydraulic pressure applied to the driven tongs. In the large diameter, manually operable tongs a suitable tension meter, load cell, or the like is affixed to a cable or chain linking the end of the tong tool moment arm to a stationary element or to a force generating arrangement and thereby obtaining an indication as to the magnitude of the force applied to the handle.
It will be observed, however, that both of the above-described conventional methods are xe2x80x9cindirectxe2x80x9d in the sense that they provide an indication of the force applied to the end of the moment arm of the jaws distant from the end of that arm in proximity to the gripping jaws. It is believed to be equally advantageous to provide the relatively small hand or manually operated tong tool with adjustable tactile sensing capability disposed in the handle of the hand tong tool, thereby providing an indication of when the preset torque setting for a particular application has been achieved.
It is a conventional practice in many manufacturing processes to employ torque wrenches, which enable the tightening of threaded fasteners such as screws and bolts and the like to a predetermined tightness through the application of a predetermined torque. Torque wrenches are known which include indicators adapted to provide a visual indication to the operator of the torque being applied so that the operator does not apply a greater torque than intended. While such torque wrenches have proven satisfactory where visual observation of the indicator is unobstructed, obvious drawbacks exist where visual observation of the torque indicator is obstructed or otherwise made difficult, as is the case in making-up threaded tubular members. To overcome this problem, torque wrenches have been developed which provide a non-visual indication to the operator when a predetermined torque has been reached, such as an audible xe2x80x9cclickxe2x80x9d or a movement providing xe2x80x9cfeelxe2x80x9d to the operator when the predetermined torque has been reached. See, for example, U.S. Pat. Nos. 2,786,378, 3,165,014, 3,577,815 and 4,467,678. However, heretofore tong type pipe wrenches have not employed such a capability.
This invention relates to a tong pipe wrench for manually making joints between adjacent threaded members such as threaded tubular members, such as pipe, or solid round members, such as sucker rods or the like. The invention is useful in connection with any tong having jaws adapted to grippingly engage one of the threaded members and further including a handle by which a manual actuating force is applied to the jaws to effect the making up of the joint between the members. In accordance with this invention, a torque wrench is adapted and calibrated to the tong head and serves as the handle portion of the tong tool and is operable to generate an adjustable, preset tactile indication of the force applied to the handle to effect the making-up of the joint. The pipe tong wrench in this case provides a non-visual indication to the operator when a predetermined torque has been reached, such as an audible xe2x80x9cclickxe2x80x9d or a movement providing xe2x80x9cfeelxe2x80x9d to the operator when the predetermined torque has been reached.
Typically this is achieved by providing a spherical coupling member interposed between a free end of a shank fixed to a conventional manual tong wrench head and an operating handle pivotally connected to and coaxial over the shank and carrying a follower which acts against the spherical member so as to maintain the spherical member within mutually opposed generally semispherical recesses in the shank and follower until a predetermined torque is reached, at which time the operating handle pivots relative to the shank with a resultant xe2x80x9cclickxe2x80x9d of the shank against the inner surface of the handle to provide an audible and sensory feel indication to the operator that the predetermined torque has been reached. A means for adjustably presetting the biasing force applied by the follower member against the spherical coupling member provides the wrench with a torque set point.
It is therefore an object of the present invention to provide manually operated tongs with a tactile and audible indication of a preset torque when a rotary force is applied thereto.
Another object of the invention is to provide a manual tong having a means for calibrating a preset torque for pipe make-up.